Burglarproof lock



March 26, 1940. H. G. VOIGHT BURGLARPROOF' LOCK Filed May 13, 1939 example,as being picked by someone with vention,Ihave shownalock comprising the usual 5 between the' pins and the drivers registers with proper position for rotation of the key barrel, 10'' 30; and the bore in the cylinder. This slight dishereinafter explained, specially,designedto, pre- Patented Mar. 26, 1940 I 1-": I I

UNITED STATES PATENT-OFFICE" BURGLARPROOF LOCK Henry G. Voight, New Haven, Conn., assignor to Sargent & Company, New Haven, Conn., a corporation of Connecticut 7 Application May is, 1939, Serial No. 273,376 2Claims. (01.. 70-419 This invention relates to looks, and more parthe key plug rotated throughaslight angle, as is ticularly to locks of the so-called pin tumbler done when an attempt is made to pick the lock; type, which have provisionfor rendering the locks Fig. 4 is a sectional view of one of the drivers. safe against unauthorized operation, such, for To illustrate a preferred embodiment of my 'inspecial tools'which are provided for this purpose. cylinder I0 having a bore within which is mount- In picking a lock of the pin tumbler type, it is ed the key barrel I I designed to receive the operthe. practice to insert a slender t'ool into the key ating key I2, the key being provided with notches slot and, raise the pins one by one until the break I3 in the bit in order to align the tumblers in the upper surface of the key plug. When a pin is as will be hereinafter explained. Secured. to the raised, the key plug is given a slight rotating rear end of the key barrel is the usual rolltorque so that when the pin is raised to the back I4. proper height the driver will stick in the exten- The cylinder ID of the lock is provided with the" M sion' or bore of the cylinder and thus remain in usual pin tumbler extension I5, and this extenthe position to permit the key plug to rotate. The I sion and the key plug I I are provided with regis- 7 pins are usually raised one by one to this positering bores I6 and I I to receive the tumblers. tion until finally the lock may be opened. I Such tumblers are normally made in two sections, It is contemplated by the present invention to one section being received in the key barreLfand provide improved means to render impossible such the other being disposed principally in the bore unauthorizedopening of the lock, and this result l6 of the extension I5, the latter being forced is accomplished by means of the fact that one of downwardly against the lower sections by the the sections of the tumblers is made in two parts, springs l8. The lower of these two sections are one of which consists of an open-ended cylinder termed pins and are shown at I9, whilethe upper.

and has a slight relative movement with respect sections of the tumblersupon which the springs to the other. This will permit a slight displacebear are termed drivers and are shown at 20. ment of the key barrel under the force of'a rotat- In the present lock one or these tumbler secing torque when the break in the tumblers is not tions, in this case the pin I9, is made of the usual in registration with the junction of the key barrel I form and size, while the drivers 20 are, as will be placement will prevent further raising of the pins, vent the picking of the lock. I and will in this manner preventunauthorized It will be seen that as-the pins I9 are of the opening of the lock. v I usual form and size, the tumbler mechanism will One object of my invention is to provide an imupy n r spa e t an is up d in t proved lock of the pin tumbler type which will be rdinary pin tu r 00k w h i t pr vi e 35 relatively burglarproof. with any burglar-proof means. This is of con- A still further object of the invention is the iderable v n a e in that he usual number of provision of a lock of the pin tumbler type pro- P s 01 tumblers may be emp 0yed W th a Cylinder vided with tumblers consisting of pins and drivers, of standard length, so that the provision of the 40 such that one of these elements will be made in burglar-proof structure does not limit the num- 40 two parts which overlap or telescope, but which ber of key changes that can be made, nor limit are so made that one of these parts will be perthe adaptability of the lock to being mastermitted lateral movement with respect to the other eyed- I to prevent the picking of the lock and wherein The second of the tumblers which is of special one of the parts will be an open-ended cylinder construction, in this instance the driver 20, is 45 having the driver spring acting directly thereon. shown'more especially in Fig. 4, and consists of To these andother ends the invention consists two parts. The outer portion of this member is in the novel features endrcombinetiens of pa a cylindrical element 2| within which is received to be hereinafter described and claimed. H the other portion comprising a stem 22 and a In the accQmpanying d awin head 23v secured to or integral with the stem. It 50 F I is a longitudinal sectional viewof a lock will be noted that the outside diameter of the embodying my invention; head 23 is substantially the same as th'e'ou'tside Fig. 2 is a transverse section on line 22 of I diameter of the cylinder 2|, and that both head. Fig. 1; v and cylinder fit relatively snugly in the bores I6 Fig. 3 is aview similar to Fig. 2 butshow'ing and vI'l, the head lying below and not entering 55 the cylindrical portion 2i. The stem 22 is received within the member 2|, but is of a size substantially smaller in diameter than the interior of the cylindrical member 2|, so that the stem 22 may be moved laterally with respect to and displaced from the center of the member 2|, until the head 23 no longer registers with the exterior outline of the member 2!.

It will be understood that in the usual form of pin tumbler lock, when the proper key is inserted the pins are pushed upwardly until the break between the pins and the drivers is aligned or brought into registration with the upper. surface of the key plug, or the break between the key plug and the cylinder. The key plug is then free to be turned by the key in the usual manner. In the present lock the proper key raises the pins l9 until the break between'these pins and the member 23 is in the proper position, and the key plug may then be rotated by the key in the normal manner. In other words, this break between the pins !9 and the heads 23 corresponds to the break between the pins and drivers in the ordinary lock, so that the normal operation of the present lock is exactly the same as one which is not provided with burglar-proof construction.

When, however, it is attempted to pick the look by use of the ordinary instrument which raises one of the pins IS until the key plug may be slightly moved under a rotating torque, this rotating torque will effect such slight movement of thekey plug when the upper surface of the head 23 arrives at the junction of the key plug and cylinder bore, as shown in Fig. 3. The key plug is then slightly displaced, this displacement being permitted by the lateral movement of the stem in the cylindrical element M. The head 23 on the stem 22 is moved slightly to one side until it is no longer in registration with the bore it in the pin tumbler extension, as shown in Fig. 3. Further upward movement of the driver is, therefore, prevented, although the key plug will be securely held against further rotation by means of the stem .22. Moreover, the person, tampering with the lock receives the indication that the pin has been raised to the proper point to permit opening of the lock, and while holding this pin at this point, proceeds to work upon the following pin. When they have all been brought to this point, it would be expected that the lock would open, but the key plug is being held against rotation by all of the stems 22, and the burglar, finding that the key plug will not rotate, must begin his operations over again, as he does not know which one of the pins is acting, or whether all of them are acting, to prevent rotation of the plug.

While I have shown and described a preferred embodiment of my invention, it will be understood that it is not to be limited to all of the details shown, but is capable of modification and variation within the spirit of the invention and within the scope of the appended claims.

What I claim is:

1. A pin tumbler lock having a tumbler xtension and a key plug; said members having registering bores, cooperating tumbler elements mounted in said bores comprising pins generally contained in the bores of the key plug and drivers generally contained in the bores oi the tumbler extension, each of said drivers comprising a pair of elements, one of said elements consisting of a headed stem, said head fitting snugly in the bore and said stem being of reduced size, and the other element of the driver comprising a hollow cylindrical member open at both ends, said member loosely surrounding, said stem and fitting snugly within the bore of the tumbler extension, and a coil spring in said bore resting against the upper edge of said cylindrical member out of contact with said stem.

2. A pin tumbler lock having a tumbler extension and a key plug, said members having registering bores, cooperating tumbler elements mounted in said bores comprising pins generally contained in the bores of the key plug and drivers generally contained in the bores of the tumbler extension, each of said drivers comprising a pair of elements, one of said elements consisting of a headed stem, said head fitting snugly in the bore and said stem-being of reduced size, and the other element of the driver comprising a hollow cylindrical member open at both ends, said member-. loosely surrounding said stem and fitting snugly within the bore of the tumbler extension, anda coil spring insaid bore resting against the upper edge of said cylindrical member out of contact with said stem, and said pins in thekey plug being of standard size and construction.

HENRY G. VOIGHT. 

